I read from Tim Marshall's articles that basically tornados before early 90s didn't take too much building quality problems into consideration when giving a rating. But I am not sure if any tornados were rated F5 based on houses of clinder block foundation . I remembered that I can only find some clinder bolck foundation houses swept away in terms of Sprio OK F5 in 1976 and it was also considered F4 rating by Grazulis. For most of F5 tornados several decades ago it's hard to investigate the details of the construction quality of these houses through some few pic like the space of each anchor bolt or the type of washers and nuts they use and install.(except for tornados like Ruskin Height 1957 which had clear photos showed these details.) When comes into era of EF scale, there was houses of 4-6ft straight nailed connection with missing bolts but strong surrounding damage had been rated EF5(Moore 2013). There was well built houses with foundation not swept clean but strong and weird surrounding damage occured had been rated EF5(Rainsville 2011). But it's hard to imagine tornados can been rated EF5 due to the damage of houses with clinder block foundation.Are there any examples of homes with cinder-block foundations being given an F/EF5 rating?
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